1. Field of the Invention
The present application relates to a composition for topical application containing nanopigments and a solid elastomeric polyorganosiloxane combined with a fatty phase, in order to improve the ultraviolet-radiation protection factor provided by the nanopigments. It also relates to the use of a solid elastomeric polyorganosiloxane combined with a fatty phase, in and/or for the manufacture of a composition for topical application to care for, treat or make up the skin or to care for the hair, containing nanopigments and having high screening properties. This composition may be applied to the human face, body and/or legs, as well as to the hands and the scalp.
2. Description of the Background
It is known that light rays with wavelengths of between 280 nm and 400 nm permit tanning of the human epidermis, and that rays with wavelengths more particularly between 280 nm and 320 nm, known as UVB rays, cause skin burns and erythema which may be harmful to the natural development of the tan; this UVB radiation should thus be screened out.
It is also known that UVA rays, with wavelengths of between 320 nm and 400 nm, which cause tanning of the skin, are liable to induce an adverse change in the latter, especially in the case of sensitive skin or of skin which is continually exposed to solar radiation. UVA rays cause in particular a loss of elasticity of the skin and the appearance of wrinkles, leading to premature skin ageing. They promote triggering of the erythema reaction or amplify this reaction in certain individuals and may even be the cause of phototoxic or photoallergic reactions. It is thus desirable also to screen out UVA radiation.
Different types of sunscreens for screening out UVA and UVB rays exist on the market: pigments and chemical screening agents. These sunscreens must be able to absorb or block out the harmful rays of the sun while at the same time remaining harmless to the user.
In this respect, metal oxide pigments are increasingly used in antisun products and day products, including make-up, given their properties of diffusing and reflecting UV radiation which gives them great value in terms of photoprotection: when used alone, they afford good protection against UV rays: when combined with organochemical screening agents, they allow highly photoprotective products to be produced. These pigments are preferably used in the form of nanopigments, the screening properties of which are well known.
Doctors are becoming increasingly aware that solar rays cause reactions which may lead to serious diseases such as skin cancer. Thus, it is increasingly sought to make antisun products and make-up or care products which have high protection factors.
For reasons of stability of these compositions and/or of toxicity on the skin or the mucosae, it is not always possible to use chemical screening agents or to increase their amounts in order to increase the protection factor of compositions containing nanopigments. Thus, the Applicants have looked into another way of increasing the protection factor of these compositions.